The present invention relates generally to communications satellites, and more particularly, to a system for detecting and isolating faults in the payload of a communications satellite.
In this communication age, content providers are increasingly investigating ways in which to provide more content to users as well as interfacing with users. Communications satellites have become commonplace for use in many types of communication services, e.g., data transfer, voice communications, television spot beam coverage and other data transfer applications. As the amount of data increases, the complexity of the satellite payload has also increased. The latest systems require each signal passing through the payload to undergo many transformations. Signal routing within the payload is highly dynamic, changing in some cases on time scales of tens of microseconds.
Traditional methods of fault detection include additional circuitry used to monitor the functioning of the various portions of the payload. Upon the detection of a fault, the circuitry provides the control center with an indication of the fault. One problem with this approach is that due to the complexity of newer satellite systems, the additional mass, power and cost of such systems is prohibitive. Mass, power and cost are resources that are desirable to reduce in spacecraft design.
It is therefore an object of the invention to provide a fault detection and isolation system that uses system signaling and thereby reduces the complexity of the satellite payload.
In one aspect of the invention, a fault detection and isolation system for a satellite communications system includes a satellite having a payload with a plurality of switches and electronic component strings having a plurality of paths therethrough. A system ground station generates a diagnostic message corresponding to at least one of the plurality of paths. The ground terminal transmits the diagnostic message to the payload. The payload generates a response signal and transmits the response signal to a control center.
In a further aspect of the invention, a method for detecting and isolating a fault in a satellite communication system includes the steps of:
generating a diagnostic message at a system ground station, said diagnostic message having a predetermined path characteristic relative to the spacecraft payload;
transmitting the diagnostic message to the spacecraft payload;
generating a response signal in the payload in response to the diagnostic message;
transmitting the response signal to a network control center;
comparing the response signal to a predetermined response; and,
when the response signal is missing or is different from the predetermined response, generating a fault signal.
One advantage of the invention is that a high level of timely payload fault detection and isolation may be performed while reducing the amount of onboard payload telemetry equipment.